Self gapping wood based panels

ABSTRACT

A wood based panel having at least one spacer, spaced at intervals or continuously, on a square edge in which the spacer will deform or be forced into an adjacent panel when subjected to linear expansion forces.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/354,471, entitled SELF GAPPING WOOD BASED PANELS,filed Feb. 5, 2002.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to wood based panels used inbuilding, cladding, and flooring.

[0003] All wood-based panel products will undergo dimensional changeswhen exposed to elevated moisture conditions. Most panels are put intoservice conditions at less than equilibrium moisture content.Consequently, there would be an uptake in moisture from the surroundingenvironment and “growth” in panel dimensions. The term used to describethis phenomenon is linear expansion, whereby physical dimensions (lengthand width) will grow with moisture uptake.

[0004] There are a number of consequences to linear expansion whenpanels 1 are fitted tightly together at joints 3 prior to expansion (seeprior art FIGS. 1-5):

[0005] 1) Panels 1 will buckle as at 4 somewhere along the unsupportedspan (FIG. 1);

[0006] 2) Excessive deflection as at 5 may result (FIG. 2), puttingfloors 10 out of level; and

[0007] 3) The upper 8 and lower 9 surfaces (top and bottom faces) of thepanel 1 will flare out as at 7 at the panel-to-panel joint 3 in arelease of forces (FIG. 3). This flaring 7 of panel edges at joints 3 issometimes attributed wholly to edgeswell, where the uptake of moisturecauses “expansion” in the vertical direction, but is more likely to be acombination of both. Flare-out 7 occurring prior to finishing thestructure would necessitate sanding, adding additional cost toconstruction. Occurrence of edge flaring 7 after finishing would causegypsum board (drywall) 21 to crack, exterior siding 25 to bulge out,floors 10 to bulge out, etc.

[0008] 4) Expansion of the floor panels may push walls 13 out of plumb(FIG. 4);

[0009] 5) Expansion of the wall system 20 might push floors 23, ceilings24 and roofs 26 off level (FIG. 5).

[0010] Given the above “expansion” characteristics and consequentimpacts are well known, most manufacturers, their third-partycertification agencies, and governing standards prescribe a minimum gapat panel joints to allow for linear expansion. The degree of gapstipulated is dependent on the inherent linear expansion character ofthe substrate (i.e., some panels will expand more than others).

[0011] Most claims and problems of the above nature presented to panelmanufacturers arise from improper installation—the panels were notgapped as prescribed. Whether due to inexperienced installers,insufficient gapping from imprecise measurement tools, or timeconstraints in building schedules, proper gapping is not being done onall product installations.

[0012] In 1976, Pettersson et al. filed U.S. Pat. No. 4,095,913disclosing a tongue and groove joint where the base of the groove isprovided with one or more protuberances to space the tongue from thebase of the groove. The protuberances are made to be deformable topermit the panels to swell without deforming the structure made from thepanels. However, it is believed that this has never been commercialized.

[0013] Thus, problems associated with wood based panels being installedwithout proper spacing has persisted for many years without solution.

SUMMARY OF THE INVENTION

[0014] The wood based panel of the present invention includes a narrowspacer projecting, at least at spaced intervals, from at least one flatedge of the panel a specified distance. The spacer width is less thanthe thickness of the edge of the wood based panel, yet the width issufficient to give the spacer enough strength to resist damage duringhandling and installation of the wood based panel. Upon linear expansionthe spacer will collapse or be pushed into an adjacent wood based panelthereby allowing multiple wood based panels to be placed adjacent to oneanother and withstand the forces of linear expansion.

[0015] These and other features, advantages and objects of the presentinvention will be further understood and appreciated by those skilled inthe art by reference to the following specification, claims and appendeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is an exploded view of buckling of prior art panels thatoccurs due to linear expansion;

[0017]FIG. 2 is an exploded view of deflection of prior art panels thatoccurs due to linear expansion;

[0018]FIG. 3 is an exploded view of flaring of prior art panels thatoccurs due to linear expansion;

[0019]FIG. 4 is a sectional view of a prior art floor system that uponlinear expansion has the capability to push walls out of plumb;

[0020]FIG. 5 is a sectional view of a prior art wall system that uponlinear expansion has the capability to expand the wall thereby pushingthe ceiling/floor/roof out of level;

[0021]FIG. 6 is a broken plan view of wood based panels of the preferredembodiment of the invention featuring two adjacent square edges and twoadjacent edges having spacer;

[0022]FIG. 7 is a fragmentary perspective view of area VII of FIG. 6;

[0023]FIG. 8 is a fragmentary perspective view of area VIII of FIG. 6;

[0024]FIG. 9 is a broken plan view of an alternative embodiment woodbased panel having a square edge, a groove edge, a tongue edge and anedge with spacer;

[0025]FIG. 10 is a fragmentary perspective view of area X of FIG. 9;

[0026]FIG. 11 is a fragmentary perspective view of area XI of FIG. 9;

[0027]FIG. 12 is a partial side view showing a method of manufacturingusing a two saw blade system;

[0028]FIG. 13 is a partial front view depicting a method ofmanufacturing using a two saw blade system;

[0029]FIG. 14 is a partial view depicting a method of manufacturingusing a single saw blade with grooved teeth;

[0030]FIG. 15 is a side elevational view of a single saw blade withgrooved teeth;

[0031] FIGS. 16A-C are a series of drawings showing the progress of thespacer deforming or collapsing in response to linear expansion;

[0032] FIGS. 17A-C are a series of drawings showing the progress of thespacer penetrating an adjacent panel in response to linear expansion.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0033] The product of the preferred embodiment of the invention, asshown in FIG. 6, is a wood based panel 30 comprised of a top surface 31and a bottom surface 32 (not shown in FIG. 6). A relatively thin, narrowspacer 34 projects from edges 33 and 35 of panel 30, while edges 37 and39 are squared off, or flush (FIGS. 6 and 7). Spacer 34 is preferablycontinuous along the length of edges 33 and 35, but may be interruptedso as to comprise plural spacers located at spaced intervals along saidedges.

[0034] The wood based panel 30 may be constructed of, but is not limitedto, the following; plywood, chip board, oriented strand board, mediumdensity fiber board, or high density fiber board. The typical dimensionsof the wood based panel 30 are four feet by eight feet. However, all ofthe panel dimensions listed below find use from time to time:

[0035] 3-foot by 6-foot

[0036] 3-foot by 9-foot

[0037] 4-foot by 8-foot

[0038] 4-foot by 9-foot

[0039] 4-foot by 10-foot

[0040] 4-foot by 12-foot

[0041] 8-foot by 8-foot

[0042] 8-foot by 12-foot

[0043] 8-foot by 16-foot

[0044] 8-foot by 24-foot

[0045] 12-foot by 24-foot

[0046] The wood based panel 30 will vary in thickness from about ¼ toabout 1¾ inch. The most typical thicknesses will be about {fraction(7/16)} to ⅞ inch.

[0047] The extent of the spacer 34 protrusion is a function of the codegap requirements where the wood based panel 30 is to be used. The spacer34 protrusion typically extends from about {fraction (1/32)} to ¼ inchform surface of edge 33 of panel 30. Spacer 34 is narrower than thewidth of panel 30. Spacer 34 should be sufficiently thick so as to notbe broken off during shipping, but sufficiently narrow, and weak orsharp to collapse, or push into the adjacent panel when subject tolinear expansion forces. The extent of spacer 34 thickness willtypically be from a maximum ⅔ of the panel thickness to a minimum of 0.1({fraction (1/10)}) inch. ⅔ of the panel thickness might especially beused for thinner panels. The optimum thickness for spacer 34 will varywith panel material used.

[0048] As shown, spacer 34 has a rectangular lateral cross section (seee.g. FIGS. 7 and 16A). However, it could be rounded, for example byhaving a semi-circular or semi-oval cross section. It could also taperto its leading edge, as with a trapezoidal or triangular cross section.It could be stepped in cross section.

[0049] In an alternative embodiment of the invention (FIG. 9), woodbased panel 40 has top surface 41 and bottom surface 42. Additionally,panel 40 has tongue edge 44 and a groove edge 45. Adjacent panels 40 areinterconnected by tongue edge 44 being inserted into groove edge 45. Incontrast, panel end edge 46 is square or flush, and a relatively narrow,relatively thin spacer 34 a projects from opposite end edge 47 (FIGS. 9and 11).

[0050] A process of manufacture is depicted by referring to FIGS. 12 and13. Wood based panel 30 is fed between two saw blades 50 at its edges33, thereby cutting panel 30 from both top and bottom surfaces 31 and32, to leave spacer 34 projecting from edge 33, between saw blades 50.

[0051] An alternate process of manufacture is depicted in FIGS. 14 and15. Saw blade 51 is equipped with grooved teeth 52 having grooves ornotches 53 therein, to allow single saw blade 51 to cut edges 33 tocreate spacer 34. Blade 51 is oriented in the plane of panel 31, ratherthan perpendicular thereto as is the case with blade 50. Thus, edge 33is cut back from its exposed face, leaving spacer 34 where the groovesin teeth 60.

[0052] In use, panels 30 or 40 are placed in abutting relationship, withspacer 34 abutting the edge 37 or 39 (FIGS. 16a and 17 a), or spacer 34abutting edge 46. As panel 30 or 40 expands, spacer 34 or 34 a is eithercrushed and collapsed (FIGS. 16b and 16 c), or is pushed into the woodof the adjacent panel 30 or 40, respectively (FIGS. 17b and 17 c). As aresult, panel buckling, deflection and flare-up are avoided, as arewalls and ceilings being pushed out of plumb.

[0053] Panel 30 may be used in numerous situations, including but notlimited to, use as indoor/outdoor floor covering, use as indoor/outdoorwall covering, or use as ceiling cover.

[0054] The above description is considered that of the preferredembodiment(s) only. Modifications of the invention will occur to thoseskilled in the art and to those who make or use the invention.Therefore, it is understood that the embodiment(s) shown in the drawingsand described above are merely for illustrative purposes and notintended to limit the scope of the invention, which is defined by thefollowings as interpreted according to the principles of patent law,including the Doctrine of Equivalents.

The invention claimed is: 1- A wood based panel for use in buildingcomprising; spaced top and bottom surfaces bounded by edges extendingtherebetween, the width of said edges defining the thickness of saidpanel; at least one of said edges including a spacer integral with andprojecting from said edge, at least at spaced intervals along said edge,said spacer projecting from said edge a distance equal to apredetermined desired spacing for said panels in order to avoid problemsassociated with improper spacing of said panel from adjacent panels, andsaid spacer having a thickness laterally of its direction of projectionwhich is narrower than the width of said edge, said thickness beingsufficient to give said spacer enough strength to resist damage duringhandling and installation of said panel, but leaving said spacersufficiently weak or sharp that said spacer will collapse or be pushedinto an adjacent panel under the pressure of linear expansion forcescaused by expansion of the wood materials of which said panel is made.2- The wood based panel of claim 1, wherein said spacer is continuous.3- The wood based panel of claim 1, wherein said spacer is interruptedby gaps. 4- The wood based panel of claim 1, wherein said spacerprojects from said edge a distance of from about {fraction (1/32)} toabout ¼ inch. 5- The wood based panel of claim 4, wherein said spacerhas a thickness of from about ⅔ of the panel thickness to about 0.1inch. 6- The wood based panel of claim 4, wherein said spacer has athickness of from about ⅔ of the panel thickness to about 0.1 inch. 7-The wood based panel of claim 1, wherein said spacer projects from saidedge a distance of from about {fraction (1/16)} to about ⅛ inch. 8- Thewood based panel of claim 1 having a thickness of from about ¼ to about1¾ inch. 9- The wood based panel of claim 8, wherein said spacerprojects from said edge a distance of from about {fraction (1/32)} toabout ¼ inch. 10- The wood based panel of claim 9, wherein said spacerhas a thickness of from about ⅔ of the panel thickness to about 0.1inch. 11- The wood based panel of claim 9, wherein said spacer has athickness of from about ⅔ of the panel thickness to about 0.1 inch. 12-The wood based panel of claim 8, wherein said spacer projects from saidedge a distance of from about {fraction (1/16)} to about ⅛ inch. 13- Thewood based panel of claim 1 having a thickness of from about {fraction(7/16)} to about ⅞ inch. 14- The wood based panel of claim 1, whereinthe wood based panel has four edges with spacers on two adjacent edges.15- The wood based panel of claim 1, wherein the panel has four edges,with a tongue and a groove on opposite edges, said spacer being on onlyone edge, extending between the tongue edge and groove edge. 16- Amethod of constructing a building comprising: providing a supportstructure; providing a plurality of wood based panels, each with spacedtop and bottom surfaces, bounded by edges extending therebetween, thewidth of said edges defining the thickness of said panel; at least oneof said edges including a spacer integral with and projecting from saidedge, at least at spaced intervals along said edge, said spacerprojecting from said edge a distance equal to a predetermined desiredspacing, and said spacer having a thickness laterally of its directionof projection which is narrower than the width of said edge, saidthickness being sufficient to give said spacer enough strength to resistdamage during handling and installation of said panel, but leaving saidspacer sufficiently weak or sharp that said spacer will collapse or bepushed into an adjacent panel under the pressure of linear expansionforces caused by expansion of wood material of which said panel is made;each of said panels including at least one edge which is free of such aspacer; securing said wood based panels to said support structure withthe spacer of one panel abutting a spacer free edge of an adjacentpanel, to thereby properly space said panels from one another. 17- Amethod of manufacturing wood based panels having spaced top and bottomsurfaces, bounded by edges extending therebetween, the width of saidedges defining the thickness of said panel; at least one of said edgesincluding a spacer integral with and projecting from said edge, at leastat spaced intervals along said edge, said spacer projecting from saidedge at distance equal to a predetermined desired spacing for saidpanels, and said spacer having a thickness laterally of its direction ofprojection which is narrower than the width of said edge, said thicknessbeing sufficient to give said spacer enough strength to resist damageduring handling and installation of said panel, but leaving said spacersufficiently weak or sharp that said spacer will collapse or be pushedinto an adjacent panel under the pressure of linear expansion forcescaused by expansion of the wood materials of which said panel is made;said method comprising: passing a panel having top and bottom surfacesand a generally squared off edge between two spaced opposing cuttingblades, one on either side of said panel adjacent said generally squaredoff edge, said cutting blade being positioned to cut away portions ofsaid top and bottom surfaces of said panel adjacent to said squared offedge, but leaving said spacer between said cutting blades. 18- A methodof manufacturing wood based panels having spaced top and bottom surfacesbounded by edges extending therebetween, the width of said edgesdefining the thickness of said panel; at least one of said edgesincluding a spacer integral with and projecting from said edge, at leastat spaced intervals along said edge, said spacer projecting from saidedge a distance equal to a predetermined desired spacing for saidpanels, and said spacer having a thickness laterally of its direction ofprojection which is narrower than the width of said edge, said thicknessbeing sufficient to give said spacer enough strength to resist damageduring handling and installation of said panel, but leaving said spacersufficiently weak or sharp that said spacer will collapse or be pushedinto an adjacent panel under the pressure of linear expansion forcescaused by expansion of the wood material of which said panel is made;said method comprising: passing a panel, having top and bottom surfacesand a generally squared off edge, through a cutting blade with groovedteeth, said cutting blade being positioned in the plane of said panel,so as to cut away the spaced top and bottom portions of the edge of saidpanel, but leave said spacer projecting from said edge.